diff --git a/moptipy/api/_process_base.py b/moptipy/api/_process_base.py
index 034c2245b..d4ba02983 100644
--- a/moptipy/api/_process_base.py
+++ b/moptipy/api/_process_base.py
@@ -535,8 +535,15 @@ def _validate_best_f(self) -> None:
                 f"{self._current_best_f}!")  # noqa
         if not isfinite(ff):
             raise ValueError(  # noqa
-                f"Reproduced the objective value {ff} of the best "
-                "solution, but it is not finite?")  # noqa
+                f"The objective value {ff} of "  # noqa
+                "the best solution is not finite?")
+        lb: Final[int | float] = self.__objective.lower_bound()
+        ub: Final[int | float] = self.__objective.upper_bound()
+        if not (lb <= ff <= ub):
+            raise ValueError(  # noqa
+                f"The objective value {ff} of "  # noqa
+                "the best solution is not within the lower and "
+                f"upper bound, i.e., [{lb}, {ub}]?")  # noqa
 
     def has_log(self) -> bool:
         """
diff --git a/moptipy/version.py b/moptipy/version.py
index 5db237574..73d8ac008 100644
--- a/moptipy/version.py
+++ b/moptipy/version.py
@@ -2,4 +2,4 @@
 from typing import Final
 
 #: the version string of `moptipy`
-__version__: Final[str] = "0.9.127"
+__version__: Final[str] = "0.9.128"